Fix an issue in the fast parser splitting.

jedi/parser/fast.py

@@ -330,6 +330,13 @@ class FastParser(use_metaclass(CachedFastParser)):
             self.number_of_splits += 1
             return text
 
+        def just_newlines(current_lines):
+            for line in current_lines:
+                line = line.lstrip('\t ')
+                if line and line[0] not in ('#', '\r'):
+                    return False
+            return True
+
         # Split only new lines. Distinction between \r\n is the tokenizer's
         # job.
         self._lines = source.split('\n')
@@ -365,7 +372,7 @@ class FastParser(use_metaclass(CachedFastParser)):
                 if m:
                     in_flow = m.group(1) in FLOWS
                     if not is_decorator and not in_flow:
-                        if current_lines:
+                        if not just_newlines(current_lines):
                             yield gen_part()
                     is_decorator = '@' == m.group(1)
                     if not is_decorator:

test/test_parser/test_fast_parser.py

@@ -181,7 +181,8 @@ def test_nested_funcs():
 
 
 def test_func_with_for_and_comment():
-    # The first newline is important, leave it.
+    # The first newline is important, leave it. It should not trigger another
+    # parser split.
     src = dedent("""\
 
     def func():
@@ -190,7 +191,7 @@ def test_func_with_for_and_comment():
     for a in [1]:
         # COMMENT
         a""")
-    check_fp(src, 2, 3)
+    check_fp(src, 2)
     check_fp('a\n' + src, 1, 3)